From: Jonathan Marek <jonathan@marek.ca>
To: linux-arm-kernel@lists.infradead.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, James Morse <james.morse@arm.com>,
Douglas Anderson <dianders@chromium.org>,
Trilok Soni <quic_tsoni@quicinc.com>,
shechenglong <shechenglong@xfusion.com>,
Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
Shameer Kolothum <skolothumtho@nvidia.com>,
linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] arm64: proton-pack: Fix hard lockup when !MITIGATE_SPECTRE_BRANCH_HISTORY
Date: Mon, 17 Nov 2025 00:12:08 -0500 [thread overview]
Message-ID: <20251117051211.16108-1-jonathan@marek.ca> (raw)
The "drop print" commit removed the whole branch and not just the print.
For some ARM64 cpus, this leads to hard lockup when
CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY is not enabled.
Fixes: 62e72463ca71 ("arm64: proton-pack: Drop print when !CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY")
---
arch/arm64/kernel/proton-pack.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c
index c7d70d04c164c..80a580e019c50 100644
--- a/arch/arm64/kernel/proton-pack.c
+++ b/arch/arm64/kernel/proton-pack.c
@@ -1032,6 +1032,8 @@ void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *entry)
if (arm64_get_spectre_v2_state() == SPECTRE_VULNERABLE) {
/* No point mitigating Spectre-BHB alone. */
+ } else if (!IS_ENABLED(CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY)) {
+ /* Do nothing */
} else if (supports_ecbhb(SCOPE_LOCAL_CPU)) {
state = SPECTRE_MITIGATED;
set_bit(BHB_HW, &system_bhb_mitigations);
--
2.51.0
next reply other threads:[~2025-11-17 5:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-17 5:12 Jonathan Marek [this message]
2025-11-23 17:50 ` Jonathan Marek
2025-11-24 14:41 ` Will Deacon
2025-11-27 1:08 ` Vladimir Zapolskiy
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